锌胁迫对海洋小球藻生长和金属硫蛋白诱导的影响

Growth exhibition and metallothioneins induction of Chlorella sp. exposed to different zinc salts

研究锌离子胁迫对海洋小球藻生长和金属硫蛋白诱导的影响,当小球藻达到对数生长期,用不同离子浓度(5、10、20、50和100μmol/L)的锌盐(氯化锌、柠檬酸锌、乙酸锌和葡萄糖酸锌)分别进行胁迫培养,通过测定小球藻的生物量和锌结合金属硫蛋白含量,考察锌胁迫对海洋小球藻的生物量、热稳定蛋白含量以及锌结合金属硫蛋白含量的影响。结果显示,当浓度分别小于5和10μmol/L时,柠檬酸锌和氯化锌对小球藻生长无显著抑制作用;而浓度为5μmol/L时,乙酸锌和葡萄糖酸锌对小球藻生长即产生显著抑制,且抑制作用皆随锌离子浓度的增加而增大。与对照组相比,4种锌盐胁迫3 d后小球藻产生的热稳定蛋白含量极显著增加,其中以锌离子浓度为50μmol/L的葡萄糖酸锌对小球藻胁迫产生的热稳定蛋白含量最高,达到34.5 mg/g(湿藻泥)。同样在此浓度的葡萄糖酸锌胁迫下,小球藻诱导产生的锌结合金属硫蛋白的含量最高。研究表明,用锌离子浓度为50μmol/L的葡萄糖酸锌对小球藻胁迫培养,诱导产生的锌结合金属硫蛋白含量达到最高。

The exhibition of growth and the induction of metallothioneins of Chlorella sp. exposed to different kinds of zinc salts were investigated. The biomass, heat-stable proteins and Zn-MTs were measured when the Chlorella sp. were exposed to four kinds of Zn^（2＋）（including zinc chloride, zinc acetate, zinc gluconate, zinc citrate）at the concentrations of 5, 10, 20, 50 and 100 μmol/L. Results showed that the growth of Chlorella sp. was not significantly inhibited when the zinc concentrations were less than 5 and 10 μmol/L for zinc citrate and zinc chloride, respectively. But the growth was significantly inhibited at the concentrations of 5 μmol/L for each of zinc acetate and zinc gluconate, and the algal biomass rapidly decreased with the increases of Zn^（2＋） concentrations for the two zinc salts. The results also showed that the amounts of heat-stable proteins significantly increased in Chlorella sp. exposed to the four kinds of zinc salts compared with that of the control group（without adding any zinc salt）, and the largest amount of heat-stable proteins was obtained when the algae were exposed to zinc gluconate at 50 μmol/L for 3 days, producing 34.5 mg of heat-stable proteins per gram of wet algae mud, which was 3.3 times higher than that of the control group. And the largest amount of Zn-MTs was induced under the inducing condition.